How to Properly Ground Poweder Coated Parts with a Dedicated Ground Rod

Improve the attraction of powder to your parts while powder coating.


If you are powder coating a metal part, it must be grounded. The ground is what attracts the powder to the part. The better the ground, the more efficient your powder coating gun can work, especially when spraying multiple coats or intricate parts. Often a powder coating gun or the guns control box will come with a small 18-gauge ground wire and a mini alligator clip that you can connect to your part to ground it. I will call this the "stock" ground. The stock ground continues through the control box, through the small gauge wire to plug into a wall outlet, and then finally reaches ground after it travels through your buildings electrical. This is not a sufficient ground for proper powder coating. No matter how good of gun you have, you need to install a DEDICATED GROUNDING ROD.
Powder Coat grounding rod


What are the advantages of using a grounding rod when powder coating?

Faraday Cage Areas:


Using a ground rod helps reduce the issues associated with Faraday cage areas. Faraday cage areas are areas of a part that are electrically shielded due to the geometry of the part. These areas are usually located in recesses or tight corners. You will notice as you powder coat, especially a more intricate part, that no matter how much powder you spray, some areas of the part remain uncoated. All of the powder is instead being attracted to the larger, more open surfaces adjacent to these areas. This results in an uneven coating with too much powder on the large areas, and bare spots in the tight areas, as you can see on the wheel below. Having a proper ground like the grounding rod will significantly reduce these problem areas and allow these areas to attract the powder more easily.


The grounding rod will help significantly, but if you are using a hobbyist-level powder coating gun, it will not cure it 100%. There are tricks that you can do to further reduce the impact of Faraday cage areas, but the most reliable method is using a professional-level powder coating gun.



Multiple Coats:


After spraying the first coat of powder and partially-curing it, you may want to apply another coat after this, whether it be clear, a translucent, or any other subsequent coat. This is another situation where a grounding rod will help. That first coat of powder acts as an electrical insulator covering the entire part. It is insulating the ground which is responsible for dissipating the charge of the powder. When spraying the next coat, if the charge is not being dissipated to ground, a buildup of charge will occur on the part, which will actually repel the powder. Without a sufficient ground, it will seem like nearly your entire part is behaving like a Faraday cage.

The proper ground that is provided by the grounding rod will allow more charge to dissipate through previous coats, making subsequent coats easier to apply. This will not be adequately accomplished by the small ground wire that is packaged with many powder coating guns. Mutli-coats are much easier after a properly installed grounding rod is connected to your part.

However, just as with the Faraday cage areas, a grounding rod can only improve multi-coats so much. With most hobbyist guns (less than $200) and a properly installed grounding rod, you will be able to apply two or three coats with somewhat minimal issues. Applying more coats than this will require a more expensive powder coating gun.


Reduced Powder Waste:


With a correctly installed grounding rod, more powder from your gun will be attracted to your part instead of ending up on the floor. This increased transfer efficiency results in less money spent on powder and a cleaner and safer shop/garage.


What is a Grounding Rod?


A ground rod is a long copper coated rod that gets driven into the ground. The sizes vary, but for the powder coating application, I recommend the length of the ground rod be at least 8 feet (10 feet would be better) and 3/4 inch diameter. If you live in a warmer area, your local hardware stores may only carry 5/8 inch x 8 feet ground rods, in which case you may have to spend a little more and buy it at Grainger. If you live in a colder area, they can be purchased at your local Home Depot or Lowe's for about $35: 3/4 in. x 10 ft. Ground Rod at Home Depot.



Ground Rod Installation


The ground rod gets hammered into the ground almost entirely. This can either be done on a ladder with a sledge hammer and a bit of effort, or if you already have or want an SDS rotary hammer, you can make quick work of it with a ground rod driver bit. You want to leave about 6 inches of the rod protruding above the ground so you can clamp the wire to it. The other end of the ground wire will connect to your parts while they are being coated, either directly or through the use of racks and hooks. For the least amount of resistance to ground, and therefore the best powder coating transfer efficiency, install the ground rod as close as you possibly can to your powder coating area.

If you plan on powder coating in your garage or shop, you can install the grounding rod right through your floor for the shortest possible distance to your powder coating area. Simply drill a hole in your garage floor with a masonry bit and a SDS+ rotary hammer, and install the grounding rod through the garage floor down into the ground below. Be mindful of any plumbing or electrical lines that may run underneath the floor before doing so. Also make sure to size your masonry bit a little larger than the ground rod so that you don't scrape all the copper coating off as you drive it down through the concrete. If you are moving and need to get rid of the grounding rod sticking through the floor, simply pound it the rest of the way down and fill the hole up with some concrete patch. Here are a couple of examples of this:




A ground rod clamp like either of the ones shown below allow you to secure the ground wire to the grounding rod. You will also need a length of wire to connect your grounding rod to where you hang your parts.  US electrical codes specify that the wire connecting a ground rod is 6-gauge or 8-gauge solid or stranded copper wire. You can use larger diameter copper wire if you prefer, but don't go smaller than 8-gauge The choice between solid or stranded won't make that much of a difference as long as the remainder of the ground rod system is setup correctly. Stranded wire is more flexible than solid, and it is capable of carrying higher current. Solid wire has less resistance than stranded wire, and less resistance is more important than current-carrying ability when it comes to dissipating the charge from powder coated parts. However, many people swear by solid and just as many swear by stranded, so I would suggest using whatever your personal preference is, or whatever is most readily available to you at the best price.



Both bare copper and insulated THHN wire will work fine to connect your ground rod to your parts. 
It is really another personal preference based on what you would prefer to install, as both meet US electrical codes and are sufficient for powder coating. If you do decide to use an insulated wire, I would recommend using green to satisfy electrical codes (in the US). You can purchase this type of wire at your local hardware store, either by the roll or by-the-foot. Since you should have a very short run between the ground rod and powder coating area, by-the-foot will likely be the cheapest option.




https://www.amazon.com/Morris-90639-Direct-Burial-8-Inch-3/dp/B005BH8OFA/ref=as_li_ss_tl?dchild=1&keywords=3/4+ground+rod+clamp+copper+approved&qid=1590392580&sr=8-3&th=1&linkCode=ll1&tag=powcoathecomg-20&linkId=40cc48e22f6e4e646e8cd48a04abfbde&language=en_US


 

Completing the Connection from Ground Rod to Part


You have the ground rod installed, and the ground wire clamped to it. Now you need to determine how you would like to complete connection to you parts. There are different methods for doing this depending on if you powder coat on a rolling rack, a stationary rack, in a spray booth, or another method.

Connecting a Powder Coating Rack to Ground Rod


If you have a large powder coating oven, you most likely will also have a rolling rack that you roll into the oven. If you powder coat your parts on the rack itself, whether its in a spray booth or not, the most common method of grounding is to connect the ground wire to the rack. The path to ground will travel from the part to a hook, then the hook to the rack, and from the rack to the ground wire. This means that the ground wire will need to be easily removable from the rack so that it can remain mobile. This can probably be accomplished many different ways but here are a couple of options.



You can use a spring loaded clamp such as a welding ground clamp or a battery jumper cable and clip it onto your rack before coating. Both of these options have been tested with good results. See the picture below for an example, just make sure to use a higher quality clamp.


If you would prefer a more solid connection, you can crimp a wire lug to the end of the ground wire connected to the grounding rod, and then fasten the lug to the rack using a bolt (or weld a stud to the rack) and wingnut. This crimp-on lug would require that you used stranded wire for the ground wire. While more secure, it is a little less convenient because you have to spin off the wing nut every time the rack needs moved.

Those are just a couple of options that you can do to connect the ground rod to the rack. The most important thing to keep in mind, whatever solution you decide on, is that there needs to be good contact between the ground wire, rack, and parts. Use as few connections to reduce resistance and failure points. Also, make sure that the contact points between every connection is clean bare metal each time you powder coat. Powder build up on the rack or part hanging hooks can reduce or completely block the path to ground.


Grounding Parts in a Spray Booth


If you hang your parts in a spray booth to powder coat or you just use a stationary rack, the tried-and-true method of connecting parts to the ground rod is by using another ground rod or even a copper pipe if you're not hanging anything too heavy. This would be done by mounting a shorter grounding rod horizontally near the top of the booth. You can use the same type of ground rod clamp on this that you used for the in-ground grounding rod to attach the ground wire. Then parts are simply hung on the ground rod inside the spray booth when powder coating. This is a very clean setup that has a minimal amount of connections. This method is shown in the two spray booths below.




Clamping ground wire from ground rod to spray booth hanging rod. This clamp can be installed on the outside of the spray booth wall to prevent powder build up.



A very helpful item to add to this type of setup is a swivel powder coating hook. This hooks onto the bar and has a swivel base that you would then hook your standard part hook from. This allows you to rotate the part while coating so you can spray all sides. It does add some extra connection points in the ground path, but these hooks are specifically made for powder coating so they are designed to maintain the ground path. It is still always smart to check the resistance with a meter to make sure.  These should stay in your spray booth and never be placed in the oven. You can clean uncured powder off of them very easily with a blast of compressed air.




powder coating on swivel hook in spray booth



Ground Parts on a Stationary Rack


Many new powder coaters and hobbyists will setup a make-shift rack to powder coat in the corner of the garage, or outside the garage door. This isn't ideal but because the part is open to contaminants and the powder is not contained, but its workable if you're just starting out. My first powder coating rack is shown below. It was setup as cheaply as possible and with as few connections as possible. I soldered the ground rod coming from the dedicated grounding rod directly to the hanging hook. This setup, while crude, was a noticeable improvement over the stock ground that came from the Craftsman powder coating gun I started out with. This setup would be easy to replicate with a swivel hook instead of a fixed hook so that you don't have to walk around the rack as you are coating.





Improving the Dedicated Grounding Rod Performance


Following the recommendations in this article will allow most people to setup a very reliable ground. However, there are some cases where more can be done to improve the dedicated ground rod system even more.

A ground rod is able to dissipate charge better when installed in moist ground. If your setup allows for it, you can possibly improve the ground more by placing the ground rod next to a rain gutter, the drip line from an AC condenser, or any area where the soil remains wet.

Some climates have very dry or sandy soils that will significantly increase the resistance between the ground rod and the ground and reduce its performance. Tests can be done to determine the resistivity of your soil so you can better determine how to overcome the issue. You can also determine what steps were taken when your building's electrical ground rods were installed so you can mimic the setup for your powder coating ground rod. You can also try contacting the relevant department in your city, or even your power company to see if they can give you advice on this issue.

A common first step to try to resolve this issue is by adding an additional ground rod to increase the available surface area to dissipate charge to the ground. Using the largest grounding rods available, they should be places at least 6 feet apart, but if you're using 10 ft ground rods, then 10 feet apart would be ideal. The two rods each need to have their own clamp, they need to be wired together, and then you would run your grounding wire to your coating area from one of them.


With the Dedicated Ground Rod Set Up, It is Time to Test


From a safety standpoint, the resistance from the ground rod to a grounded part should not exceed 1 Megaohm (10^6 Ω or 1,000,000 Ω). From a powder coating performance standpoint, you want the resistance to be as close as possible to 0 Ω. The correct tool to accurately measure the resistance from ground rod to part is a Megohmmeter.


Now that you know how to set up a proper dedicated grounding rod, its time to set one up yourself.  It is worth it! I noticed improvements immediately. Second coats sprayed like they were the first coat and Faraday cage areas were minimized to only the tightest areas.

67 comments:

  1. VERY GOOD (and useful) INFORMATION! Keep it coming man!

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    1. Big tanks powder coating coFebruary 22, 2018 at 12:50 PM

      You. Helped. Me. Alot. I. Bought. A used. Kci. System. And. Took. It. All. Apart. Then. Mounted. In. My. Shop. Wall.works. Good. Will. Send. Pictures. Soon. Tks

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  3. Can you explain why such a heavy grounding wire is needed? This is carrying very little current.

    Great site, by the way. There is very little info on powder painting out there. Not a single book that I could find!

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    1. I am definitely not an expert selecting wire size for the required current. A lot of very good powder coaters use a heavy gauge wire to ground their work so I do and teach the same. I wish I could tell you that I tested it with a smaller gauge wire and saw huge improvements when I went with the heavy gauge but I never tested it. I just used the heavy gauge wire as soon as I set up my ground rod and never looked back.

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    2. Anything over an 8 gauge wire is totally unnecessary and even a 8 gauge is probably total over kill. If you look at some of the professional powder coating guidelines produced by companies such as Wagner and Parker Ionics they recommend an 8 gauge wire for an automated powder coating line. Resistance in most any gauge wire in lengths under 100' is almost nil. Increased wire gauge is necessary for high amperage loads or to protect from lightning strikes, neither of which come into play in powder coating.

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    3. Same reason long distance power lines are high voltage, these guns are kV so resistance will be minimal. The real problem with relying on the stock ground clip is *reliability.* Anyone who's dug into an old or shoddily built building's wiring knows how suspect they can be! My current location had a proper ground setup but the clamp had badly corroded which was not obvious until fiddled with. That's worth sorting if only for safety but if powdercoating is your livelihood it makes sense to cut out the black box of in-wall wiring if there's any doubt whatsoever.

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  4. I am starting up a business on the side and while I knew a good bit about it, there are some very helpful points

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    1. I am glad you have found the information helpful so far. I have plans to start writing new information before the end of this month so make sure you check back. Thanks for the comment.

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  5. You have an amazing site, so much info. I want a powder coating setup now! About the ground wire, does this require the powder coating machine to be grounded too, via the electrical plug to the wall socket? Or is the ground to the earth all you need? What do you do with the small ground clip, just leave it on the table connected to nothing? Thanks from Denmark!

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    1. Thank you for the comment, I still have plenty of more info to write. You are correct with the ground wire, once you ground your parts through a grounding rod, you can leave the ground clip for the gun disconnected. I just keep mine rolled up and out of the way.

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  6. What wire are you using to connect to your rack? Don't appear to be 8 gauge bare. Stores carry only 8' ground rod in 5/8 or 1/2" which would you recommend?

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    1. I use 8 gauge wire. The pictures in the article are of my first setup but I changed it to 8 gauge at the time of writing the article. I would recommend the 5/8" ground rod as it has more surface area.

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  7. It's not mystery where that ground goes when you plug your machine in, in the USA it better go to a ground. If you do not have a good ground you had better call an electrician. That ground is suppose to go back to the box where it is connected to a grounding rod into the ground like the one you are making, if not then every thing in your house is not properly grounded and you can die from electrical shock. You can check the ground by reading the hot to that ground and seeing that you have full voltage, if not that lower voltage is the amount that is not going to the ground. If you see 90 volts and you have 120 input, that means 30 volts can go through you from any appliance you use if you touch something like a faucet that acts as a ground. That's my two cents.

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    1. Luckily, my house hasn't killed me yet so I'm sure it is properly grounded. When it comes to powder coating, the dedicated ground rod is a tried and proven method that gives better results over using the ground clip that comes with powder coating guns. I was just joking around with the "mystery" comment. I don't actually know how about intricacies of building electrical or where it actually grounds at, definitely not my area of expertise. Thanks for reading, and thanks for the info!

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    2. I have no powder coating experience and am in the research stage.
      So far you have answered all the questions I have been looking to answer and you do it in a manner that is easy for someone with absolutely no knowledge of powder coating that is easy to visualize and understand.

      Thank you and well done

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    3. Sean, you should listen to Anonymous up there, and google "lightning Step potential" and read the NEC as it pertains to ground electrodes before dismissing his advice. You should not be advising anyone to install a ground rod that is not bonded to the rest of the home's ground system.

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    4. Yes, legally ALL ground rods in your house/building MUST, MUST be bonded together. Hint, won't hurt you to do it, you just get an even BETTER ground. And even better than a ground rod is a UFER ground system, which I believe is now required in new construction. It is basically that all the rebar in your foundation is electrically tied together, and you actually ground to that. The HUGE surface area of the concrete makes it into a great ground

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  8. Thanks for the info, my question is , I have both harbor freight gun and Eastwood gun. After I use the rod ground method , you said that I don't need the alligator clip anymore, but do I still need to plug the equipment to an outlet?, or just hook my air line to the gun and not worry about the power and the pedal and button that you press when operating. Thanks for prompt response

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    1. You definitely still need to plug it in. Don't forget that the powder coating gun is providing a charge to the powder as you spray it out of the gun. If you don't plug it in or operate the foot pedal, then the powder would not be charged and it would not be attracted to the grounded part. Let me know if you have any more questions. Thanks for reading.

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  9. Hi, I just built my spray booth and I'm running a copper ground bar across and plan to hang parts on copper ground hooks. Will my setup be effective as yours?

    Thank you.

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    1. That sounds like a great setup as long as the hanging copper rod is hooked to a ground rod in the ground. As long as all the connections are nice and tight and you use as few connections as possible, you can't go wrong.

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    2. Hi Sean, thanks for responding. However, I'm curious. How necessary is it to have a ground bar into the ground? Can't I just clip the ground wire from the guns control box onto my hanging ground bar?

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    3. The ground rod in the ground is the most important part of the setup. Once you connect your parts to the grounding rod in the ground, you don't even need the clip from your gun. The whole point of the ground rod is to provide a better ground than the powder coating gun clip can provide.

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    4. Yes, that makes total sense. I was trying to figure it out last night after reading this article and kept replaying it over and over in my head until the light finally turned out. Ground rod it is! Thank you for all the informative information!! Great site!

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  10. From an electricians point of view this makes no sense, you need a good ground to the source of the high voltage, which is the control box, the only way to improve this is use a larger cable from your part to the control box.
    If you are connecting your part to the ground rod only, you are then relying on the general mass of earth as a conductor and it will have a much higher resistance than your "stock" ground which is entirely copper.

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    1. The idea of using a grounding rod for powder coating is not mine. I read about it, tried it, and noticed unquestionably improved results when shooting more than one coat. Grounding rods are very widely used in powder coating from small shops, to huge high-production factories. It is the only recommended way I have ever read about to ground parts for powder coating. It has been written about it technical articles, The Powder Coating Institute, even some of the manufacturers of professional powder coating guns.

      I am not an electrician, nor do I know the exact science behind why it offers better results, but it is a tried and true method that I will continue to use and recommend.

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    2. I too am trying to reconcile what I know about electricity and HV generation (as an EE with 35 years of experience) as compared to what seems to work practically. I don't know how powder coating systems are designed but if I were designing one I would electrically isolate my ground from earth ground so I could build up the largest voltage potential between my part and the gun tip. Adding earth ground to the equation is unnecessary and potentially (no pun intended) counter-productive because paint would then want to stick to anything at earth ground potential. I will nevertheless try this. I can tell you that heavy gauge wire is definitely unneeded. The difference between very fine wire versus thick will make no difference when voltage potential is in the thousands of volts with high impedance (i.e. low current capability). They effectively have a very large resistor in series with the voltage at the gun tip which prevents much current from flowing. Adding a wire with, say 1 ohm of resistance, effectively adds that resistance in series with that very high resistance. I have difficulty seeing how a better earth ground could make a measureable difference. You might improve the path to ground by a 10th of an ohm which is probably about one part in 1,000,000. However, as I said I will give it a try to see it I can see a difference myself.

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    3. Unfortunately, I know very little about the intricacies of electricity so I can only partially follow what you are saying. I also cannot argue "electrically" why the grounding rod works better. However, is is a tried and true method in the powder coating industry from large production factories to custom shops. I will tell you 100% that there is a very noticeable improvement with the grounding rod.

      Just recently I moved and did some powder coating using the grounding clip on the gun because I did not set up my grounding rod yet. I thought there was something wrong with my gun, half of the powder ended up on the ground and shooting powder into the tight areas was near impossible. I set up my grounding rod the next day and it was a night-and-day difference. The length of time spent coating was shortened quite a bit, I wasted much less powder, and I was able to do 2 coats easier than just one coat while using the gun clip.

      I believe you mentioned isolating the earth ground from the gun ground, however, when using a grounding rod, I recommend ditching the gun ground all together, there is no reason to even connect it to the part.

      This topic has been quite controversial so I think I will shoot a video to compare the two methods.

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    4. Very good Sean, yes I can see your point about grounding and it does make all the sense in the world. I don't know why it would be questioned. The more strands of wire also adds to the conductivity as electrons actually travel around each strand and not through it. Great job on this entire article by the way!!

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    5. This is incorrect. You want more strands for flexibility, not conductivity. Electrons only move to the surface of a conductor when there is no electric field (they are all like charges, like charges repel and will migrate away from each other). Once you connect a conductor to a voltage source the electrons will flow through the whole wire, not on the surface. This is why your house is wired with solid conductors - you don't need the flexibility since they never move once they are in the wall. Welding cable has a ton of conductors because you are constantly moving the welding head, not because the conduction is only on the surface.

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  11. I grounded for wire like you said to and when I apply powder it seems to stick on the part.. once it starts to cure spots seem to open up... and bare metal is exposed.. almost like cracks in the powder. do you know why this is? thanks

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    1. I grounded "my" wire not for wire.

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    2. That sounds like poor prep work. Wipe down the part with a lint-free rag using acetone or Pre cleaner. Heat the part up to about 200, remove from heat and give it one more wipe down while trying to to burn your fingers :) Powdercoating results are usually based more on prep work than gun work.

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  12. hi Sean I would like to say thank you for sharing your knowledge and experience with us. Question, I live in an apartment complex and I cant go out because its too cold. I have everything to powder wherever my hands can grab, now and then the external grounding where can I plug in or put it or something, because I want to do it or play around with it, inside of my apartment?

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    1. Well coating in an apartment is probably not the best idea, you'll probably end up with powder on everything. However, I would probably do the same thing if I had no choice. I would definitely built a spray booth with a fan and a filter to capture as much over-spray as possible. If your apartment is not on the 1st floor, there is no way around it, you will not be able to use a grounding rod realistically. You'll have to use the grounding clip on your gun. However, if you are on the first floor, I would stick the grounding rod right outside the door and use a wire with a connector at the grounding rod so you can easily disconnect it and bring it inside when you are not coating. When you are coating, just run it under the door.

      I doubt any of this would be allowed by your apartment so this is all a do-at-your-own-risk type of thing.

      What type of oven do you plan on curing the parts with inside your apartment? Do NOT use your kitchen oven of your apartment unless you never plan to use it to cook food with and you plan on replacing it when you move out.

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  13. What kind of wire connector did you use?

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    1. I'm currently using some 8 gauge stranded copper cable. Nothing fancy.

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  14. Question . My company has just moved in a powder coat booth ,they want me to get it up and going. Where it came from it had no ground rod.. I'll fix that .But what I noticed was the ground wire for the parts was connected to the metal booth ??Wont this pull the powder away from where you need it? I'm going to be moving racks of parts in and out all day .Looking to making a ground strap on each rack with a magnetic connection ,like on some of the newer kitchen appliances, just a magnetic cord connection.

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    1. It is not uncommon for the powder coating booth and racks to be grounded as well as the part. It will attract a very minimal amount of powder as long as you are not directly aiming the gun at the booth or rack. The part can be grounded to the booth as long as the booth is grounded to something, ideally, a ground rod. However, the fewer connections between the part and the grounding rod is the best way. So if you have the part hanging on the rack which is then grounded to the booth which is then grounded through the ground rod, you have several connections there can increase the resistance. I would prefer to ground the rack directly to the grounding rod and ground the booth through a separate connection to the grounding rod. Make sure that your rack always has a clean bare spot when hanging parts though. A magnetic connection would be fine and that is a neat idea as long as it does not increase the resistance of the ground path.

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  15. Can I use the same grounding rod that grounds my house electrical panel or do I need a separate grounding rod for powder coating?

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  16. Maybe some of the uncertainty about grounds in these comments is from not completely realizing that the powder coating guns work by putting a *static* charge on the powder particles. We're much more used to examples of electricity as a current flowing in a complete loop (e.g. a "circuit").

    A good example of static charge is when you were a kid in the wintertime and you shuffled your feet across the carpet. This built up a static charge, which you then dissipated by touching your brother's arm and shocking the dickens out of him.

    A powder gun uses the output of it's high-voltage transformer to set up an electric field. The field generator is the little wire thing at the end of the gun barrel. The compressed air fluffs (good word!) the powder, and sends it across the the electric field and out the end of the gun barrel. As each particle of powder crosses the electric field, it picks up a charge; just like you did when you were shuffling your feet across the carpet. Although the exact amount of charge taken on by each powder particle will vary, each particle will be charged with the same polarity: a negative polarity since all electrons always carry a negative charge (positrons carry positive charge).

    So, we've got this air stream headed out of the powder gun, and it's loaded with powder particles that each contain a negative charge.

    Like 2 magnets, where similar poles repel and opposite poles attract, electrical charges behave similarly: two particles with the same polarity of charge repel each other, but different polarities attract. With the powder in the air stream, they all have negative charges, so they (faintly) repel each other. Good thing, or they would clump together in mid-air and you'd have a mess.

    Now, the air stream with the charged powder particles comes in contact with the Ferrari Dino valve cover you're restoring. The valve cover is well grounded to Mother Earth: it contains 0 electrical charge. As the negatively charged powder particles hit the valve cover, they're attracted and they stick to the cover.

    Now, here's the reason the excellent quality ground is needed: As more and more charged powder particles come in contact with the valve cover, some of their negative charge is passed to the valve cover. This is exactly like when you shocked your brother. You were the powder particle, and you transferred a good bit of the charge you had built up over to your brother (the valve cover). If you have a poor quality ground (either resistive, or not making good electrical contact with Mother Earth) the negative charges will build up on the valve cover until it is nearly as negative as the powder particles themselves. Bummer: additional powder doesn't stick as well, and the existing powder is much more likely to fall off the valve cover.

    If you get a good quality connection between the valve cover and Mother Earth, it will constantly drain the charge off the valve cover and leave the cover at 0 volts potential, which will be attractive to the powder particles!

    Mr. Castle is correct to use thick wire (less resistance per foot) and to optimize his ground rod by soaking the earth around it in water.

    I hope this is useful to all. I also hope it's actually correct, since I'm writing it at 4AM.

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  17. Sorry, I forgot to mention something important: If you use a separate ground rod and wire as Mr. Castle suggests, then you should probably also do the following:

    1) The grounding pin on the powder gun's power supply's AC cord that you plug into the wall is still absolutely necessary. It grounds the chassis of the power supply. Do not cut off or otherwise disable the AC cord's grounding pin.

    2) Don't use the grounding wire and clip that connect the powder gun's power supply to the object being painted. Just cut it off or tape it up. Having two grounds is almost always a bad idea. The power supply generates thousands of volts; why take the chance for no benefit?

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    1. Thank you for the clarifying the ground rod. If its okay with you, I'd like to summarize your post and add it to the article to add some more clarification for people who doubt its effectiveness.

      And yes, to anyone reading this, do not cut off the ground pin on your powder coating gun's electrical plug. If you, there is a chance of getting a shock from the gun as it is no longer grounded. The newer Redline EZ50 guns have no grounding pin and that is exactly what happens: it shocks the users. That is why you must actually ground the gun to a grounding rod using the ground clip.

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  18. Certainly you are welcome to summarize, edit and include my comment; no attribution is needed. I'm glad you think it is a worthwhile comment!

    These are deadly voltages we're dealing with. If the manual for your powder gun contradicts something I've written, it's probably for a damn good reason and you should do exactly what the manual tells you to. Each manufacturer has designed their own circuit to generate the high voltage required. Mr. Castle pointed out the new Redline EZ50 guns having plugs with no ground pins: this really surprised me. I imagine the circuit they designed to generate the high voltage creates it's own isolated ground on the high voltage side. I looked around on the internet today trying to find schematics of the EZ50 and other commercially available powder guns, but I could not find any.

    So, my hands are kind of tied as far as exact recommendations on the ground wire between the gun and the object being painted goes. To say for sure, I'd need to see the electrical schematic for the particular gun being used. What I can say with reasonable confidence is:

    1) Always do what the manual specifically says to do. Always.

    2) If the AC power cord is a three-prong cord, then insert it into a three-prong wall outlet that you are totally confident is actually connected to your home or shops electrical ground. Assuming that you're using Mr. Castle's ground rod and wire, there may or may not be a need to use the ground wire connecting the gun to the object being painted. I can't tell without seeing the particular gun's schematic. Do what the manual says to do.

    3) If the AC power cord is a two-prong cord, that's OK, but you're almost certainly going to have to attach the ground wire between the gun and the object being painted whether you use Mr. Castle's ground rod or not.

    You should get a licensed electrician out to look at your installation if:

    A) You're not absolutely positively certain that the AC wall outlet is truly connected to ground.

    B) You get sparks when you do the following:
    1) Turn the the gun's power supply off.
    2) Fully discharge the gun by the method recommended by the manual.
    3) Leave all the wiring hooked up as if you were going to paint.
    4) The ground wire between the gun and the object being painted will have
    an electrical clamping terminal on the end to clip it onto the object
    being painted. Put on thick gloves, and hold the electrical clamping
    terminal. Drag it across the bare-wire end of Mr. Castle's ground rod
    wire, like you were striking a match. If you see sparks, then you have a
    problem with your building's ground that requires a licensed electrician
    to examine and fix.

    I hope this is helpful.

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  19. From Rod Danglewood:. Thanks to Mr. Castle for all the outstanding information. I have one small contribution to add. During my 20 years in the USMC, I was aware that our utilities and communications guys would mix in water softener salt to the backfill that went in around grounding rods for portable generators. These high output MEPDS power systems needed a solid ground and the salt made the soil around them much more conductive, depending on soil type. The water you add doesnt conduct elecrical current by itself, but the electrolytes in it do (deionized/distilled water is a poor conductor). The water also creates more surface contact between the ground rod and the soil. I dont know how much, if any, this would benefit powder coating but I thought I would make the observation.

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  20. Can I use the existing grounding rod that my house is grounded to or does it need to be a dedicated rod?

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    Replies
    1. The overall consensus is that you should always use a dedicated grounding rod. I don't have any experience otherwise though.

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  21. someone told me about a neg side of a battery. run a wire from bat to part..is this true? thanks very great advise here...

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    Replies
    1. No, absolutely not. You should either use a dedicated ground rod (preferred) or the electrical clip that is attached to your powder coating gun box.

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    2. ok thank you.......i learned alot here.....

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  22. i get less spark when it's graund'ed to mother earth..more alot more when doing it with the power box...when turn'ed on of cores..is this normal?

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  23. Hi I live in Hawaii where the ground is...rock. volcanic rock. You can't drive anything into the dirt more that a foot or two. I work out of a large industrial building, can I ground to the building (even though I doubt the foundation is deeper than a couple feet)??? What are my alternatives? Ive got the craftsman gun and doing a small motorcycle gas tank.

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    Replies
    1. In this situation, you have me stumped. I wouldn't know what to do except to use the green grounding wire attached to the Craftsman gun. If you can get in touch with a local electrician, they might know what to do in this situation but its a long shot. I wish I could offer better advice but I have no experience with terrain like that. You may not be able to use a dedicated grounding rod, but on the bright side, at least you live in Hawaii!

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    2. Sean, (new guy here).. I am curious if, for this situation, it would help him if he used the ground hole of another outlet..

      I realize this could be considered fairly dangerous, but if he was to use a thicker wire and jerry rig a way to only plug it into the grounding hole on another outlet (maybe on another breaker), do you think he'd see improvement?

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    3. In situations where a long copper rod can't be driven deep enough into the ground, the copper rod can be replaced with a large copper plate which is dug into the ground. The larger sized copper plate, the better.

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  24. Great site. I ran power to my detached garage a couple years ago, could I use that ground rod as my ground for powdercoating or should I run a dedicated rod?

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    Replies
    1. Thanks. A dedicated grounding rod is always considered ideal.

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  25. Really learned a lot here and solve a lot of my problems. I am working with Eastwood dual voltage gun . I am coating when the part is hot because I can't add seconds coat or that I can't get the powder to get in some areas. Good result so far . Any way my house fuse box is right next to my painting booth . Can I run my grounding to the green/yellow grounding in the box ????

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  26. Great site, lots of information. My question is, I get fish eyes on my second coat while applying the clear or candy color. I have a harbor freight powder coating gun, will the ground rod resolve my problem or should I buy a better quality gun as well. I will try the ground first, but I want to make sure I get quality results. What type of gun are you using Sean?

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    Replies
    1. If you are getting fish eyes, its not because the gun or the grounding rod, but most likely due to contamination of some type. After you apply the first coat, make sure to only handle the part with clean gloves until you spray the second coat. Make sure that the powder itself is not contaminated by applying it on a test piece. Make sure if you are blowing it off with compressed air that your air is clean and dry.

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  27. Hi thanks for the good info :) I'm installing a dedicated chemical earth rod tomorrow in the UK (3m x 22mm cooper pipe, with removable cap-vented, filled with rock salt).
    My question is can/should I fit two 3.26mm (8 gauge) earth wires to the rod, one to the rack and one with a clip to the part hook?

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  28. Just got round to making a dedicated ground rod.
    It makes a massive difference, I now have no problems at all when doing 3 coat applications . I used to have to leave the part warm to get the 2nd and 3rd layers to take, now it's just spray like the first coat for all three.

    Thank you very much for the really helpful tips on this site.

    Stew

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  29. (New guy here) AWESOME input from you all! Going to set up my own sytsem here and will apply everything you all have taught me here! Thank you from Myrtle Beach, S.C.

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  30. Hi Sean. I'm from the UK and recently been looking at ways to improve the ground for when I'm painting alloy wheels. I've been working for a family business now for 2 years and when I started I had never heard of powder coating let alone used this method. I went in at the deep end and just got on with painting wheels. The method they used from day one, was to paint the wheels at around 165 degrees C. 2 years in and I'm now looking more Into changing that method by doing them at a much cooler temp or from cold (after de gassing them) I'm using a Wagner system and the technician step by step shown me how to set the machine up and he also used the (stock) grounding clip. However over time I have gained experience on reading up on the grounding rod idea. When I'm powdercoating I'm finding more powder is covering the ceiling of the booth and in some cases myself. I have come to realise recently that the whole booth is grounded. I'm guessing this is because we don't use a ground rod at the moment...also the stock ground is connected to the bar which we hand the wheels on 1 at a time. We don't use the frame method...we have 2 runner rails attached to the ceiling and have hooks hanging down from them. Once the wheels come out the oven at 165 degrees C we then transfer the wheel from the rail to a bar at the front end of the booth that runs horizontally across with a hook in the middle to hang the wheel. That bar is attached to the frame of the spray booth....all this being metal...I'm now beginning to think that not only have we been grounding the bar with the wheel which we are painting. But also the whole of the spray booth is grounded. So recently to test this i have been painting the wheels at a much less temp...or cold to see what happens. I have noticed I'm getting that (cage effect) on most areas of the wheels not just the tight corners. So this has now led me to believe although our method works well...we still need to add the grounding rod and attach the wire from that to the part we are painting. By us painting the wheels hot I'm starting to think that we are in some was cancelling out the grounding method as the wheel is that hot...as soon as the powder hits the wheel, it's instantly melting to the wheel but at the same time powder is attracting to most of the booth. However the finish on the wheels after the bake is 9 times out of 10 perfect. What I have noticed is during my research I have watched videos of wheels being painted and after applying the primer coat...they go straight on top with the colour then the clear coat. Where we have found that this just peels straight off in some cases...so we prep between each coat. Allowing the next coat to have something to key to. So now after reading up your grounding rod method I'm beginning to think this will cut out a lot of prep time and powder loss. With a good ground it will allow for the primer to stick to the bare metal alloy...then the colour to stick to that and then the clear coat to stick to that without prepping between coats right?? Also during my research I haven't come across a single person who powder coats wheels hot. They all do them cold as I have seen people Hoover off parts of the powder to allow a 2 tone affect. All this is a massive learning curve for me going forward as I want What is best for us as a growing business as well as what's best for a longer lasting finish to the customers wheels.

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  31. Think I lucked out. I had another garage built onto my house for a shop. The electician added a sub panel and a ground rod in the system. will be doing my first powder coat this week. This is a great site for good info, thank you, D.

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